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Characterisation of ‘Starking’ apple polyphenoloxidase
Author(s) -
Rocha Ada M C N,
Cano M Pilar,
Galeazzi Maria A M,
Morais Alcina M M B
Publication year - 1998
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/(sici)1097-0010(199808)77:4<527::aid-jsfa76>3.0.co;2-e
Subject(s) - chlorogenic acid , chemistry , extraction (chemistry) , acetone , chromatography , enzyme , substrate (aquarium) , catechol oxidase , food science , botany , biochemistry , biology , polyphenol oxidase , peroxidase , ecology
Experiments were performed to optimise the extraction conditions of ‘Starking’ apple fruit polyphenoloxidase (PPO), to evaluate the affinity and specificity towards several substrates and to study the stability of enzyme extracts from apple samples stored under different conditions. Sodium phosphate buffer (0·2 M , pH 6·5) plus 0·25% Triton X 100 and 1% or 2% PVPP was found to be the most efficient extraction medium. Chlorogenic acid, dopamine and 4‐methylcatechol showed similar specificity towards PPO, and chlorogenic acid was found to be the best substrate for the enzyme. Enzyme extracts from frozen cut apple stored at −4°C, and extracts from lyophilised apple samples stored at 4°C were more stable than extracts obtained from fresh‐cut or acetone powder samples. © 1998 SCI.